Kubota B5100 utility tractor specs and service data

The Kubota B5100 is a sub-compact utility tractor model manufactured from 1978 to 1984 by Kubota in Japan. It was available in two-wheel drive (B5100E) or four-wheel drive (B5100DT) versions.

The Kubota B5100 is equipped with a 508 cc (31.0 cu·in) two-cylinder diesel engine with 68.0 mm (2.68 in) of the cylinder bore and 70.0 mm (2.76 in) of the piston stroke, and a gear shift transmission with 6 forward and 2 reverse gears and dry single plate clutch.

The Kubota B5100 utility tractor features:

The Z500-A1 diesel engine which produces 12.0 PS (8.8 kW; 11.8 HP) at 3,000 rpm of horsepower
Ball screw type steering
Mechanical wet disc brakes
Open operator station with two-post ROPS
Category I rear hitch with 140 kg (309 lbs) of maximum lift capacity
Front PTO with 3,000 rpm
Transmission type rear PTO with 540/1,000 rpm

General specifications

General Specifications
Model	Kubota B5100
Tractor type	Sub-Compact utility tractor
Production years	1978-1984
Factory	Japan
Dimensions and weight
Length	1,820 mm (71.7 in)
Width	920 mm (36.2 in)
Height (steering wheel)	1,120 mm (44.1 in)
Wheelbase	1,180 mm (46.5 in)
Ground clearance	2WD (rear axle): 260 mm (10.25 in) 4WD (front axle): 210 mm (8.67 in)
Front tread	2WD: 660 mm (26.0 in) 4WD: 670 mm (26.4 in)
Weight	2WD: 365 kg (805 lbs) 4WD: 405 kg (893 lbs)
Fuel capacity
Fuel tank capacity	8.0 liters (2.1 US gal.; 1.8 Imp. gal)

Engine

Engine
Engine model	Kubota Z500-1A
Engine type	4-stroke, vertical, two-cylinders
Displacement	508 cm³, (31 cu·in)
Cylinder bore:	68.0 mm (2.68 in)
Piston stroke:	70.0 mm (2.76 in)
Compression ratio:	22.0:1
Max. horsepower	9.5 PS (7.0 KW; 9.5 HP) at 3,000 rpm
Max. torque	–
Cooling system	Liquid-cooled
Lubricating system	Forced lubrication by pump
Combustion chamber	Spherical type
Fuel injection pump	Bosch K-Type Mini Pump
Injection type	Indirect injection
Injection nozzle	Bosch throttle type
Fuel used	Diesel fuel No.2-D
Starting system	Electric starter (12V, 0.8 kW)
Starting support device	Glow plug in combustion chamber
Governor	Centrifugal ball mechanical governor
PTO shaft rotation	Counterclockwise (from PTO shaft side)
Dimensions (L x W X H)	520 x 380 x 504 mm (20.5 x 15 x 19.8 in)
Dry weight	69.7 kg (153.7 lbs)
Cylinder compression pressure
Cylinder compression:	31.5 kgf/cm² (3.09 MPa, 448 psi)
Compression differential limit between cylinders:	10% or less
Valve clearance
Intake valve clearance:	0.150-0.200 mm (0.0059-0.0078 in)
Exhaust valve clearance:	0.150-0.200 mm (0.0059-0.0078 in)
Oil system
Lubrication system:	Forced lubrication by pump
Oil type:	API CC or CD
Oil capacity:	2.3 liters (2.43 US.qts, 2.02 Imp. qts)
Oil filter:	Full flow paper filter (cartridge type)
Oil pressure:	At idle spped: 68 kPa (0.7 kgf/cm², 10 psi) At rated speed: 196-441 kPa (2.0-4.5 kgf/cm², 29-64 psi)
Fuel system
Injection timing:	25° B.T.D.C.
Fuel injection pressure	13.73-14.71 MPa (140-150 kgf/cm², 1991-2133 psi)
Cooling system
Thermostat’s valve opening temperature:	80.5-83.5°C (176.9-182.3°F)
Temperature at which thermostat completely opens:	95°C (203°F)
Coolant capacity:	3.0 liters (3.2 US.qts, 2.6 Imp. qts)

Transmission and chassis

Chassis, steering and brakes
Chassis	B5100E: 4×2 2WD B5100DT: 4×4 MFWD 4WD
Steering type	Ball screw type
Brakes	Mechanical wet disc
Final drive	Internal-expanding type, right and left independent with interlock device
Front axle differential case	0.5 liters (0.53 US.qts, 0.44 Imp. qts)
Front axle gear case	0.15 liters (0.16 US.qts, 0.13 Imp. qts)
Transmission
Transmission manufacturer or model	–
Transmission type	Gear shift with dry single plate type clutch
Gears	6 forward and 2 reverse
Speed	Forward: 12.8 kmh (8 mph) Reverse: 6.4 kmh (4 mph)
Transmission oil capacity	8.5 L (2.2 US. gal, 1.9 Imp. gal.)

Tires

Tires
Front tires	Ag: 4.00-9 (2WD); 4.50-10 (4WD) Lawn/turf: 18×6.50-8
Rear tires	Ag: 7.00-16 Lawn/turf: 27×8.50-15

Rear Hitch

Three-Point Hitch
Category	I
Control type	–
Lift capacity (at ends)	140 kg (309 lbs)

PTO (Power take-off shaft)

PTO
Front PTO type	–
Front PTO speed	3,000 rpm
Rear PTO type	Transmission
Rear PTO speed	540/1,000 rpm

Electrical system

Electrical system
Ground	Negative
Charging system	12V
Charging amps	–
Battery	12V 35Ah

Hydraulic system

Hydraulic system
Hydraulic type	Open center
Pressure	1710 psi (117.9 bar)
Pump flow	3.1 gpm (11.7 lpm)

Author: Sergei Wers
About: Co-founder and CEO of a multi-brand auto repair shop (engine repair, chassis repair, body repair and painting) for over 15 years. I have been developing internet sites with technical specifications for more than seven years.

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Kubota B5100